If your projects aren t all AnyCpu then you may also want to check that the following 2 settings match:

1. [Right click test project] -> properties -> Build -> Platform target - e.g. x64

2. [Main Menu] -> Test -> Test Settings -> Default Processor Architecture -> X64

I found that when these didn t match my test project would silently fail to run.

I had to change my async test methods to return Task instead of void.

The tests were then active and runnable in Test Explorer.

If you are using NUnit rather than MSTest then you will need either the NUnit 2 Test Adapter or NUnit 3 Test Adapter for Visual Studio ≥ 2012/2013.

I had the same problem in VS 2017. In my case it solved by restarting VS.

You can view the error-output of your test runner by opening the Output panel (view-->output) and choosing "tests" from the "Show output from" dropdown

Additionally, if you have Resharper installed you can open a test file and hover over the test-circle next to a test to get additional error info

Clicking that will bring you to a window with more detailed information. Alternatively, you can open that window by going to Extensions --> Reshaper --> Windows --> Unit Test Exploration Results

TLDR: Update the testing packages, look into the output -> test console

I struggled with this for a day and a half. so here s what I did to solve it:

Symptoms

1. 5 Unit test projects, all discoverable in TestExplorer
2. 2 out of 5 executed properly
3. 3 stating not run at all
4. The problem started after a .net framework update

Investigation

Since all the packages were updated during the .net framework update, I started with the differences between the working and not working projects. The first clue was that all 3 projects were using: MSTest.TestAdapter and MSTest.TestFramework

Naturally I went to the -> Output console -> Test dropdown in VS 2019 and looked at the output. Nothing useful there.

Step one of the solution: Update the MSTest.TestAdapter and MSTest.TestFramework to version 2.0.0

Step two of the solution: Now the Output console -> Test dropdown output started showing one after the other, missing packages and wrong binding redirects

Step three of the solution: Manually add the missing packages. For me those were

1. System.Runtime.Extentions
2. System.Reflection
3. Maybe some more that I m missing

Step 4 of the solution: Removed/Fixed the unnecessary binding redirects.

I hope this will help someone else.

Check what framework the tests are written against (e.g. nunit, xunit, VS test, etc.) and make sure you ve got the correct test adapter/runner extension installed.

For me it was NUnit 3 Test Adapter that was missing and I confirmed the version number required by looking at the nunit.framework dependency version (select the .dll in the Dependencies tree in Solution Explorer and hit F4 to bring up the Properties window).

I found that in the project it was not referencing the Microsoft.VisualStudio.QualityTools.UnitTestFramework assembly. Instead, it was referencing Microsoft.VisualStudio.TestPlatform.TestFramework and Microsoft.VisualStudio.TestPlatform.TestFramework.Extensions. When I removed those two references and added the reference to the Microsoft.VisualStudio.QualityTools.UnitTestFramework assembly the tests that were previously marked with the blue exclamation point suddenly became active and started working.

Install Nunit3TestAdapter Nuget has solved this problem

Clean-Rebuild solution worked for me.

I had this issue and for me it was caused by having multiple Test Projects with different versions of :

• MSTest.TestAdapter
• MSTest.TestFramework

Consolidating the nuget packages for the projects so they were the same resolved the issue for me.

What fixed it for me was upgrading the MS.Test nuget packages

Had same issue after clean install of VS 2019. Tests are found but not run with "Unexpected error occurred". Fixed by setting up x64 instead of x86 which was selected by default.

In my case, it was because one test project in my solution had the MSTest.TestFramework and MSTest.TestAdapter nuget packages installed but the others did not. These packages were apparently not required to run tests until one project in the solution had them installed.

The issue was fixed by installing those packages on test projects missing them.

In my case I had an async void Method and I replaced with async Task ,so the test run as i expected :

    [TestMethod]
    public async  void SendTest(){}

replace with :

    [TestMethod]
    public async  Task SendTest(){}

Have tried many options with Visual Studio 2019 Version 16.4.6 and Microsoft.VisualStudio.TestTools.UnitTesting, but for now the only way to run tests successfully was by invoking next command in console

dotnet test

Tests are discovered in Test Explorer but outcome is "Not Run".

Updating Visual Studio did not help.

Have resolved issue with "No test matches the given testcase filter FullyQualifiedName" by running updates to latest version for next packages:

Microsoft.NET.Test.Sdk
MSTest.TestAdapter
MSTest.TestFramework

Setting Processor Architecture for AnyCPU Projects in Test Explorer fixed my issue! See screenshot above.

I am using XUnit and was missing the xunit.runner.visualstudio package. Installing it and my tests ran.

I managed to figure out the reason for VS 2019/2022 skipping some tests by running the test cli with blame option:

vstest.console.exe myproject-test.dll /blame

This will generate an xml file with one test with "Completed="False".

In my case, the test host process crashed due to a memory access violation while running that test. The memory access violation was caused by an infinite recursion. You can right-click and debug that certain test.

With Visual Studio 2019 and test project targeting .NET 5.0 you need to install also xunit.runner.visualstudio. So, your packages should be like in this example:

• xunit (2.4.1)
• xunit.runner.visualstudio (2.4.3)

I had different version of NUnit (3.11.0) and NunitTestAdapter (3.12.0) nuget packages. When I updated NUnit to 3.12.0, Visual Studio ran tests.

In my case it worked to update the MSTest nuget packages. Could reproduce this problem even on blank MSTest project and updating the packages worked.

Had the same symptoms, in my case it was the dotnet core SDK version that was the problem.

The projects was targeting 2.2, and was able to build using 3.0. After installing newest 2.2 SDK version they were able to run.

I changed "Debug" to "Release" and it worked again (Any CPU.)

I had a different solution to get my tests to run. My global packages folder didn t match what was in my .csproj This is what my .csproj looked like:

I had to change my Version to 16.5.0 which i found was installed in my global packages folder. Now my tests are able to run:

What works for me is to delete the bin folder, then rebuild the project.

After struggling for hours on VS 2022, the solution for me was to install both: NUnit and NUnit3TestAdapter nuget packages

When using both MSTests and NUnit tests it is possible to mix them. Also, remove other testing frameworks NuGet packages. Remove, Clean solution, Rebuild

This is the case:

[TestFixture]
public class NUnitTestClass
{
    [TestMethod]
    public void MSTestMethod()
    {
         // Will detect it but it won t run
    }
}

I had same symptoms.

Please ensure you have the proper Visual Studio extension installed via Tools - Extensions and Updates. In my case, I had to install XUnit and Specflow from the Online option.

Then clean the solution and rebuild it.

If that still doesn t help, clear your temp directory (search for %temp% in the Start menu search and delete all contents in Temp)

And then finally try uninstalling Resharper which finally fixed my problem.

Here it was the test project was not marked to be built:

Build -> Configuration Manager... -> check build for your test project